In many parts of the country immigrants are doing the work Americans no longer want to do, especially the hard work of manual labor at construction sites.

In our reporting we discovered that most of them are paid a fair wage — $14.00 an hour for an entry level construction job, and that they are paying state and federal taxes through withholding. (Sure, some employers pay cash off the books but most we encountered are trying to play by the rules).

While local residents are conflicted about the spreading Hispanic culture - language and music - they agree the immigrants are very hard workers and in general have good family values.

But it is also clear the immigrants are straining the public and health systems without paying their fair share.

They live in overcrowded, often sub-standard housing in clear violation of local laws.

They're brazen about acquiring forged documents — from Social Security cards to driver's licenses — to get work.

And, most important, this complicated problem won't be solved until Mexico becomes a reliable partner in improving its own economy and enforcing the rules at its border.

We can build a high fence, send illegals back, crack down on employers and it won't end because it is about survival and a piece of the American dream, a powerful lure for immigrants from all over the world for 200 years.

It is a growing problem and it requires urgent action in Congress because in the meantime all the pressure is on local law enforcement, school and health administrators and employers.

A sovereign nation must have control of its borders and a great nation must have a systematic, legal way of filling its labor needs.

Dateline wires the home of a volunteer, Jenny, from top to bottom with hidden cameras. Then she called repairmen to her house for a simple problem we created as a test with Jenny's pool. NBC's Chris Hansen reports.